The Crystal Growth Process Of Optical Interferometry

In situ Observation of crystal growth of the transparent model metal is an effective method to study solidification of metal. It has great significance in recognizing metal organizational structure and controling crystallization mechanism. It is paid attention to by researchers and producers in material field for a long time.In this article, we designed two apparatus to study the process of crystal growth: one was the room of crystal growth, the other was the observation and measurement apparatus. The morphology of growing interface and the mechanism of formation using the 99% succinonitrile transparent models metal and succinonitrile-5at%water as a transparent model alloy were experimentally studied respectively on the observation apparatus by controlling the growth condition parameter. Then we analysed the influence of the outside growth condition on the morphology of growing interface. The main content and the conclusion of this article is as follows:Set the room in the Mach-Zehnder interference system.It is the first time to show the relationship of interface morphology of 99% succinonitrile transparent models metal and the change of the interference fringe.The research indicated that interference fringe shape changes obviously in the interface of crystal growth in the crystal growth;In a certain gradient of temperature and speed of growth, there were dendrite and branching of dendritic tip in the interface. As a result of gradient of temperature and gravity, the stripe curving direction was different in the interface of crystal growth.The growth mechanism of regular and irregular interface of succinonitrile-5at% water as a transparent model alloy in different condition was studied by phase contrast microscope. The formation of cell, dendrite and irregular interface morphology--seaweed crystal and degenerated crystal in the crystal growth was observed.It was showed that the cell formed in the interface of small amplitude when the interface of smooth was perturbed. After branching of the tip, elimination and competition, the stable cell formed;In a strong amplitude, branching of the tip was not happened in the interface of smooth. Then there was only elimination and competition developed rapidly to form stable dendrite in the interface. The interface was unstablewhen the cell and dendrite coexisted, cell changed into dendrite in company with rapid speed.When crystal growth along with certain crystallographic orientation, the surface tension tended to the isotropism. If the speed of interface was increased, the interface morphology was transformed into the degenerated crystal by a seaweed crystal. The degenerated crystal was in the dynamic change. It meaned that the orientation of secondary arms changed, the orientation of secondary arms tended to the direction of interface growth gradually and primary arms was substitute by secondary arms.